一种频域多路径电磁干扰对消方法

针对实际环境中背景干扰相关性差导致干扰对消误差较大的问题，提出一种频域多路径电磁干扰对消方法。利用变分模态分解(VMD)的分频特性将两通道信号分解为多个具有相同中心频率和分解带宽的模态信号，利用分解后的模态信号构造多路径干扰对消系统。然后利用反向传播(back propagation, BP)神经网络对每一路径上的信号进行非线性拟合并对消，从而获得真实的被测设备(EUT)辐射发射信号。结果表明，与真实EUT辐射发射信号相比，所提方法得到的EUT辐射发射信号功率误差低于1 dB且信号相关性高于96%;与变步长LMS算法、EMD-LMS算法相比，功率误差至少降低3.6 dB,信号相关性至少提高15%。所提方法对在开阔场中大型、可移动的EUT电磁辐射发射原位测试研究具有参考价值。

A frequency domain multi-path electromagnetic interference cancellation method

In response to the issue of substantial interference cancellation errors arising from insufficient background interference correlation in actual environments, a frequency-domain multi-path electromagnetic interference cancellation approach was proposed. The frequency splitting property of the variational modal decomposition (VMD) was used to decompose the two-channel signals into multiple modal signals with the same center frequency and decomposition bandwidth. Then the decomposed modal signals were used to construct a multi-path interference cancellation system. Finally, a back propagation (BP) neural network was used to nonlinearly fit and cancel the signals on each path so as to obtain the real equipment-under-test (EUT) radiated emission signals. The simulation and experimental test results show that the EUT radiated emission signal obtained by this method has a power error of less than 1 dB and a signal correlation of more than 96% compared with the actual EUT radiated emission signal. Compared with the variable step size LMS algorithm and EMD-LMS algorithm, the power error is reduced by at least 36 dB, and the signal correlation is improved by at least 15%. This method has a reference value for in-situ testing of electromagnetic radiation emissions from large, movable EUTs in open fields.